If you have a patient about to undergo surgery you should advise them to contact their doctor to plan the best way to manage their warfarin treatment.

The doctor will need to consider the benefits versus the risks of stopping your warfarin.

Patients with a low risk of a blood clot at the time of surgery may be advised to stop their warfarin for a few days before surgery and asked to restart immediately after surgery.

Patients with a high risk of developing a blood clot may be changed from warfarin to low molecular weight heparin a few days before surgery. They may also require heparin after surgery.

Monitoring around surgery

The patient will need close monitoring around the time of surgery

  • If the INR result is in the range 2-3 it usually takes about 4 days for the INR to fall to 1.5 or less on stopping warfarin.
  • Most surgery can be safely performed with an INR of less than 1.5.
  • After restarting warfarin it usually takes 3 days for the INR to return to the correct treatment range.